Diverter systems may be used in conjunction with performance of subterranean operations which involve retrieval of hydrocarbons from subterranean formations. Diverter systems are traditionally fixed to the bottom of rotary beams of a drilling rig, below the rig floor. The purpose of a diverter system is to provide low pressure control over a well by diverting well fluids away from the drilling rig when performing subterranean operations such as, for example, during the preliminary stages of drilling. A typical diverter system may include a housing supported with its bore beneath the rotary table on the platform, and having one or more side outlets from the bore for connection with drilling mud return lines on the platform. A typical diverter system may also include a diverter assembly. A typical diverter assembly may include a tubular body adapted to be lowered into a supported position in the bore of the housing. The tubular body may have one or more ports each aligned with a corresponding side outlet from the bore. The typical diverter assembly also may include a spool, having an overshot packer at its lower end. The spool may be suspended from the tubular body for lowering over the upper end of a conductor extending upwardly from the preventer stack as the tubular body is landed in the bore of the housing. More particularly, the tubular body may be sealingly coupled to the housing bore to confine flow within the tubular body into the side outlets with flow normally returning to the rig mud system from which it may be recirculated into the drill string.
Packers may be adapted to be lowered into and landed in the diverter body to seal about a drill string extending downwardly from the rotary table and through the tubular body leading to the conductor. Accordingly, drilling fluid returns may run through the drill string and be “diverted” into overboard lines connected to the outlets in the housing with reservoirs on the platform.
Prior art systems of this type are traditionally used in marine drilling rigs, particularly with floating drilling equipment. In certain applications, it may be desirable to adapt diverter systems to be used with land rigs. It may also be desirable to reduce the costs associated with traditional diverter systems by coupling the diverter assembly to the conductor, thus eliminating the need for a housing.